Thanks for the idea. Twin studies are fascinating.Scandinavians have produced a lot of excellent work in this area.

Thoughts:1-It seems that investment behavior and biases are, in a large part, directly related to genes (which eventually could be "scored" for potential ability...). Also, there is an indirect effect: the fact that you are drawn to read Ben Graham or Warren Buffett may explain more about future investment decisions than the act of understanding the concepts described by the mentors. That may explain why people say that value investing comes "naturally".

3-Also, do you want to know that you will develop a non-preventable disease for which there is no satisfactory treatment?

There are still grey areas. When my kids do well, I tell them it's genes. Otherwise, it's because of their environment. One can alter the course and some may achieve large deviations but genes are dominating, in a Darwinian sense.

A devil, a born devil, on whose natureNurture can never stick; on whom my pains, Humanely taken, all, all lost, quite lost ... The Tempest, Shakespeare (1611)